There is accumulating evidence to indicate that interferon production may be somehow involved in, or at least associated with, the immune recognition mechanism in general. This proposal is to study: (1) the temporal role of interferon production in spleen cell cultures, and (2) relationship of interferon production to the many responses which occur in normal and in sensitized leukocytes when they are exposed to antigen or mitogen. Studies concerned with the mechanisms whereby the various factors (interferon, antibody, lymphotoxin, migration inhibitory factor, chemotactic factor, etc.) interact in leukocyte cultures may be of help in elucidating the mechanism of interferon production and its relationship to cell mediated immunity and to other fundamental functions of the cell.